Scheduled charging problem

[Yknot]

2020 MY vin: 0006xxx, software V 2020.48.35.5. So tonight about 6:34 I set the schedule charging to 11:30pm and plug the charging adapter that came with the car in to the car. The battery was at 73%. A couple of minutes later the charging starts tonight at 6:37pm which is not the 11:30pm that is set. This seems to be the normal mode for my car with no change for the past several software updates. Does anybody have an idea of what I’m doing wrong or not doing right?

 

[jcanoe]

When you specify scheduled charging in the Tesla you are indicating when the local electric utility's off-peak rate period ends (presumably when the grid utilization starts to increase). With the Tesla you can't specify to start charging at the earliest possible time unless you turn off scheduled charging and just start charging immediately. When scheduled charging is enabled the Tesla vehicle will always calculate the latest time to start charging that will complete prior to the end of the off-peak period.

Right now your Tesla thinks your off-peak window ends at 11:30 PM so it starts charging almost as soon as you plug in so it will complete charging by that time, usually at least 15 minutes before the end of the off-peak charging window. Most off-peak periods are from 11PM to 6AM or 7 AM. Tesla used to always default to 0600 being the end off-peak period but now you can set when the off-peak rate period ends.

 

[DonaldBecker]

This is one area that Tesla falls short of Chevrolet. Their system allows entering the off-peak times, a variation for weekdays/weekend, and a summer/winter variation with start dates. It applied this only to home charging, assuming that you wanted to immediately charge elsewhere, and it had a quick override by double inserting the cable for immediate charging.

I expected that Tesla would have a better system, but it is far worse. It manages to be simplistic while still being confusing.

 

[Electric700]

What if you switch to Scheduled Departure (e.g. may be set to be ready by 7 AM) for two or three days and see how charging adjusts? If you then switch back to Scheduled Charge Start, what happens? See also the video below. If you continue having trouble, you may want to report the issue using the Tesla app.

 

[Rocky_H]

There are two settings, though: scheduled start or scheduled end. Make sure you know which one you're picking. If you just pick a scheduled start time at 11:30 PM, it should start only at 11:30 PM, not try to do back calculations of when it should begin. I think people sometimes make this harder than it needs to be.

Granted, they could still do better, by offering to let you pick different start times on weekdays versus weekends.

 

[DonaldBecker]

There are two settings, though: scheduled start or scheduled end. Make sure you know which one you're picking. If you just pick a scheduled start time at 11:30 PM, it should start only at 11:30 PM, not try to do back calculations of when it should begin. I think people sometimes make this harder than it needs to be.

Granted, they could still do better, by offering to let you pick different start times on weekdays versus weekends.

This isn't sufficient to keep the car from continuing to charge through peak hours, and it doesn't let you effectively use mid-day off-peak hours (with morning and evening peak hours).

 

[Rocky_H]

and it doesn't let you effectively use mid-day off-peak hours (with morning and evening peak hours).

Where in the world is that a thing? Mid day is the higher part of the load on the grid, and I can't imagine a utility that would have a middle part of the day be off-peak. Does your utility actually do that?

 

[DonaldBecker]

Where in the world is that a thing? Mid day is the higher part of the load on the grid, and I can't imagine a utility that would have a middle part of the day be off-peak. Does your utility actually do that?

That's a failure of imagination. It's a pretty obvious cost structure where solar PV makes a significant mid-day contribution to the grid.

A minute with Google found a current TOU plan that has morning (5AM-9AM) and evening (5PM-9PM) peak rates, with mid-day off-peak:

SRP Time-of-Use Price Plan

 

[Rocky_H]

That's a failure of imagination.

That's statistical likelihood.

It's a pretty obvious cost structure where solar PV makes a significant mid-day contribution to the grid.

Non-obvious, because solar PV's effectiveness and therefore market penetration is where there is very high sun load, which is most in the summer and is therefore high A/C use in the afternoons--an unlikely time to be off peak.

A minute with Google found a current TOU plan that has morning (5AM-9AM) and evening (5PM-9PM) peak rates, with mid-day off-peak:

SRP Time-of-Use Price Plan

Whoa--that is really wild--central Arizona. As I was thinking, that's not through most of the year when you get most of the sun, but that's only November through April, and it has two separate peak times in the day. That is very interesting and unusual. I guess that does make some sense, though, where the solar production is down through the winter, but the extremely heavy air conditioning load would be way WAY down. OK, that's fascinating.

 

[DonaldBecker]

That's statistical likelihood.

Non-obvious, because solar PV's effectiveness and therefore market penetration is where there is very high sun load, which is most in the summer and is therefore high A/C use in the afternoons--an unlikely time to be off peak.


Whoa--that is really wild--central Arizona. As I was thinking, that's not through most of the year when you get most of the sun, but that's only November through April, and it has two separate peak times in the day. That is very interesting and unusual. I guess that does make some sense, though, where the solar production is down through the winter, but the extremely heavy air conditioning load would be way WAY down. OK, that's fascinating.

There was also recently a PGE TOU plan with a split peak (albeit with a partial-peak mid-day rate, not off-peak), but I couldn't find it with quick search. PGE doesn't make it easy to find superseded rates.

The point still is that a simple "finish charging before.." or "start charging after.." rule is both difficult to understand and falls short of what is required. It's clearer to have explicit time ranges for charging.

Of course Tesla could easily leapfrog to much better: "I see that your home is in PGE territory. Would you like the PGE EV2-A charging schedule? We'll notify you if the times change."
or
"Your home is in the MarsEP service area. Would you like automatic dynamic demand charging?"

 

[frankvb]

My SDG&E EV-TOU5 rate (and other rates using a similar pricing structure) has additional "super off peak" times in March and April from 10AM to 2PM on weekdays. IMHO that is just to annoy solar panel owners like myself, as generation will then only yield 8.5c instead of 25c when the output of the panels is highest. I guess A/C load is low while PV output is high.

In weekends it extends to 2PM all year round (as opposed to 6AM on weekdays).

 

[jcanoe]

When you specify scheduled charging in the Tesla you are indicating when the local electric utility's off-peak rate period ends (presumably when the grid utilization starts to increase). With the Tesla you can't specify to start charging at the earliest possible time unless you turn off scheduled charging and just start charging immediately. When scheduled charging is enabled the Tesla vehicle will always calculate the latest time to start charging that will complete prior to the end of the off-peak period.

Right now your Tesla thinks your off-peak window ends at 11:30 PM so it starts charging almost as soon as you plug in so it will complete charging by that time, usually at least 15 minutes before the end of the off-peak charging window. Most off-peak periods are from 11PM to 6AM or 7 AM. Tesla used to always default to 0600 being the end off-peak period but now you can set when the off-peak rate period ends.

I spent some time with the most recent scheduled charging / scheduled departure settings. That is some CF. I finally thought I had it figured out but there was one last step before my Model Y was set so that the Tesla will finish charging just prior to the end of the off-peak charging time instead of beginning to charge right away. I had to tap the elongated button for Scheduled Departure and the button turned blue.

I know SpaceX is a separate company; when it comes time for the manned mission to Mars I hope the crew doesn't have to use such garbage software when it is time to fire the retros.